Laser cooling of solid state matter has been demonstrated through various experiments as early as 1995 (R. I. Epstein et al., “Observation of laser induced fluorescent cooling of solid”, Nature 377, 500-503 (1995)). Basically, a laser is focused to introduce photons into solid state matter containing specific ions. Heat is present in the solid state matter in the form of excited photons in the specific ions. The photons introduced by the laser increase the excitation of the photons in the specific ions until the photons are radiated as fluorescence, the photons of which carry some of the heat away from the solid state matter. The cooling that occurs is referred to as “optical cooling” or “laser cooling”. In some materials the fluorescence may be reabsorbed by impurities in the solid state matter, resulting in a reduction (or even reversal) in the cooling procedure.
A specific equation has been developed for the net power transferred to the solid state matter from the laser (R. I. Epstein et al., “Advances in laser cooling of thulium-doped glass”, J. Opt. Soc. Am. B 20, 1066-1074 (2003)). If the amount of energy radiated is greater than the laser energy added, cooling occurs. The net power transfer equation describes the probability that an excited ion will emit a photon that is emitted from the solid state matter, referred to as the “external quantum efficiency (EQE). Two basic conditions that dictate net cooling are a high EQE and high purity materials in the solid state matter. In the prior art these conditions are met, at least partially, through the use of various rare-earth ions in fluoride or chloride glasses and crystals with low phonon energy.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
An object of the present invention is to provide laser cooling of modified wafers, including SOI wafers and the like.
Another object of the present invention is to provide laser cooling of modified wafers and the like that include electronic circuits and components.
Another object of the present invention is to provide laser cooling of hot spots in modified wafers and the like.